In the past, a forgotten object detection system using a radio tag has been proposed to prevent forgotten objects such as teaching materials in a case in which children go to school.
As an example, a portable communication device including a reader that reads tag data of a radio tag installed in an object located within a readable range and a control unit that detects a forgotten object by extracting tag data of a radio tag installed in an object to carry on the basis of schedule data in which a schedule is associated with an object used for the schedule and comparing the extracted tag data with the tag data read through the reader is disclosed in JP 2014-44522 A (Patent Document 1).